The invention relates to a smoking machine for testing cigarettes and the like by drawing smoke therethrough in a manner closely simulating human smoking of cigarettes, and for optionally testing the cigarette smoke therefrom. Prior art devices in the field of the invention, such as shown in U.S. Pat. Nos. 3,460,374 and 3,433,054 are successful in simulating human smoking, however, they generally have very restricted operational parameters. For instance, the "puff" duration and interval have not been readily adjustable, nor the flow through the cigarette during a puff. For instance, U.S. Pat. No. 3,460,374 provides a device having a generally constant volume cylinder for receiving smoke from a cigarette holding means, which limits the puff duration achievable, and U.S. Pat. No. 3,433,054 provides a sequentially movable indexing means, which limits the adjustability of the puff interval.
According to the present invention, a smoking machine is provided that has easily adjustable means for varying smoking parameters over a wide range, including the puff duration, interval, and the flow, such means being associated with one or more smoking ports for varying the flow characteristics of each port.
According to the present invention, a source of substantially constant vacuum is provided. Solenoid-operated valve means are provided for selectively providing operative communication between the vacuum source and holding means for the cigarettes to be tested or dummy flow resistance means for simulating the resistance to flow of the cigarettes in fluid circuit parallel with said holding means. The flow through each cigarette is adjusted by a variable flow valve in fluid circuit with the cigarette and vacuum source, and may be tested by a flowmeter in the circuit. A by-pass for the flowmeter is provided so that it is not constantly subjected to smoke passing therethrough. A reservoir is provided connected to a vacuum pump, and a relief valve is associated with the reservoir. A manifold is provided between the vacuum source and each of the cigarette holding means.
It is the primary object of the present invention to provide a smoking machine with widely variable smoking parameters. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.